You might have already found the answer to this question, but does this help at all? aws.amazon.com/blogs/aws/… As long as the VPC is set with an IPV6 block, you should be able to select the "dual-stack" option on your load-balancer. For testing, I normally just use the curl -6 method for checking for IPV6 availability, example: curl -6 https://www.google.com, and nslookup -query=AAAA to confirm IPV6 DNS responses, example: nslookup -query=AAAA www.google.com.
– devnullNov 5 '18 at 1:40